1. Field of the Invention
The present invention relates to a polymer panel with a sealing membrane for making electrical and mechanical connections through the panel. The invention further relates to a method of processing such panel.
2. Technology Review
Traditionally, vehicle door assemblies have been made out of an outside panel 3 and an inside panel 2, see FIG. 1, which are stamped from steel and welded together using many smaller pieces of steel for additional structural performance. The metals depending on the thickness give good stiffness. Further, these assemblies have included a means for sealing the interior passenger compartment from the exterior moisture. This sealing means generally takes the form of a piece of plastic film 5, or the use of grommets or sealants to seal the holes for mechanical or electrical connections made in the inside door panel 2.
With the increased demand for fuel efficiency, however, automobile manufacturers have in recent years looked for new materials to replace these traditional materials in automobiles. The materials of choice for most automobile manufacturers have been polymers. Manufacturers have attempted to integrate polymers anywhere they could in the structure and the body of the car to reduce the weight, and therefore increase the fuel efficiency. Manufacturers realized that a significant reduction in weight could be obtained by reducing the weight of the door panels. Therefore manufacturers have produced vehicle door panels which are either partly or entirely made out of polymer resins for this purpose.
One of the drawbacks of using polymers is the moduli of elasticity of polymers. Because of the low modulus of elasticity relative to traditional steel, polymers are sometimes considered to lack the stiffness required for automobile body parts. This drawback has been partially solved by the addition of fillers to the polymer resin which increases the modulus of elasticity and therefore the stiffness.
Conventionally, when a panel 2 is molded from resin, it creates the need to add an additional process step to cut a hole into the inner panel to allow for the mechanical or electrical connections. Additionally, if a hole is molded into the panel 2 by injection molding, the hole must be sealed with a grommet or weatherseal material such as a rubber gasket because resin does not flow smoothly around the hole and cracks often occur around the periphery of the hole.
The additional processing steps of cutting access holes result in an additional manufacturing expense, and wasted material which must be cut out of the panel. The door then like a metal door must be sealed with a plastic sheet or the holes must be sealed with a grommet or a gasket to maintain a good weatherseal between the exterior side surface of the panel 4 and the interior side surface of the panel 5. These additional processing steps increase the costs for parts, labor and assembly.